Shares of Chiquita Brands International CQB soared Monday after the banana giant got an unsolicited takeover offer that could scuttle its plan to pursue a tax inversion by buying Irish rival Fyffes.

Orange juice supplier and agribusiness firm Cutrale Group and Safra Group, an international group of companies that invests in banks and other businesses, offered to buy all of Chiquita's outstanding shares for $13 each, or nearly $611 million.

The bid, which the Cutrale-Safra team said was not subject to financing, represents a 29% premium to the stock's $10.06 closing price on Friday.

The proposal came five months after Chiquita said it would combine with Fyffes to become the world's largest banana-distribution company, with a projected $4.6 billion in annual revenue. The deal had been proposed as a corporate inversion that would reduce Chiquita's U.S. taxes through Chiquita's reincorporation overseas. Several U.S. firms have proposed similar transactions in a surge of inversion interest this year.

But the White House has attacked corporate inversions, with President Obama arguing that U.S. firms that use the tactic are "gaming the system." U.S. Treasury officials last week said they were exploring potential ways to block inversions unilaterally.

Cutrale and Safra predicted it might be possible to close their proposed acquisition before the end of the year "without the execution risk and uncertainty" surrounding the inversion plan in light of the Obama administration criticism.

"Together, we are confident that this transaction offers more compelling and more certain value for Chiquita shareholders as compared with the proposed transaction with Fyffes and significantly enhances Chiquita's business potential," Michael Rubinoff, leader of the Cutrale and Safra senior management team, wrote in a letter to Chiquita board Chairwoman Kerrii Anderson and CEO Edward Lonergan.

Chiquita said its board of directors would review the offer in consultation with the firm's legal and financial advisers and "determine the course of action that it believes is in the best interests of the company and its shareholders."

"Chiquita shareholders are advised to take no action at this time and to await the Board's recommendation," the company added, saying it would have no further comment on the Cutrale-Safra offer until the review has been completed.

David Holohan, an analyst at Merrion Capital in Dublin, told Bloomberg News Monday "the market clearly is attributing value to the new bid as opposed to the old tie-up between Fyffes and Chiquita."

Chiquita accounts for an estimated 22% of global banana exports by volume, according to Banana Link, an England-based not-for-profit that works for fair and sustainable banana and pineapple trades. The company said it has more than $3 billion in annual revenues, employs more than 21,000 and operates in nearly 70 countries around the world.

Headquartered in Brazil, the Cutrale Group said its global business operations include orange, apples, peaches, lemons and soybeans.

Safra Group, which has major Brazilian subsidiaries, said it has more than $200 billion of assets under management and approximately $15.3 billion in aggregate stockholder equity.